Lanmark Group listed on sinobi ransomware leak site
Brooklyn-based construction firm Lanmark Group has been listed on the leak site of the threat actor known as sinobi.
- Published
- 2 min read
- 2 min read
- Ransomware group: sinobi
- Country: United States
- Sector: Professional Services
- Announcement date: December 16, 2025
Sinobi ransomware group targets Lanmark Group
The Brooklyn-based construction firm Lanmark Group has been listed on the leak site of a threat actor known as sinobi. The announcement, which appeared on December 16, 2025, claims that the organization's systems have been encrypted by the attackers.
Ransomware attacks of this nature typically involve a process known as double extortion. In such scenarios, threat actors not only encrypt an organization's critical data to disrupt operations but also exfiltrate sensitive information to use as leverage. By threatening to release this data on a public leak site, attackers aim to pressure the victim into paying a ransom to prevent the exposure of proprietary or sensitive information.
Details of the claim
According to the post made by sinobi on December 16, 2025, the threat actor claims to have successfully compromised the firm's data. The group has issued a ransom demand of 7,800,000 USD in exchange for the decryption of the systems and to prevent further data exposure. While the attack was announced on the same day as the claimed compromise, public information regarding the specific capabilities and history of the sinobi group remains limited.
Potential data at risk
The listing does not provide specific details regarding the nature of the compromised data, and no specific file counts or data sizes were disclosed in the announcement. However, based on the organization's business model, it is assessed that documents related to the company's construction projects and business operations may be at risk.
- Construction project documentation
- Business operation records
About Lanmark Group
Lanmark Group is a full-service general contracting firm headquartered in Brooklyn. Founded in 2005, the company specializes in managing complex construction projects for a variety of clients. The firm serves as a trusted partner for both public and private sector clients, including state and municipal agencies.
Impact and industry implications
This claim may create negative impacts on the company's operational continuity and commercial reputation. Given the firm's involvement in both public and private sector projects, secondary risks such as supply chain attacks or targeted phishing campaigns may emerge as a result of the breach.
As a United States-based entity, a potential breach could trigger legal obligations under state-level data protection laws and various sectoral regulations. The high ransom demand suggests that the threat actor may be specifically targeting the company's financial capacity.
For organizations operating within the professional services and construction sectors, such incidents highlight the necessity of robust cybersecurity frameworks. To mitigate risks, organizations should consider implementing comprehensive security measures, including regular system reviews, multi-factor authentication, and continuous monitoring to defend against potential data breaches. Maintaining strict adherence to data protection regulations is also essential for managing legal and reputational risks following a security incident.